.whole {
    height: 100000px;
    margin: 0 auto;
    width: 100%;
}

.w {
    background: linear-gradient(to bottom, black, white);
    width: 100%;
    height: 1000px;

}

.get {
    position: fixed;
    left: 50%;
    top: 0;
    margin-left: -600px;
    margin-top: 0;


}

.header {
    width: 480px;
    height: 200px;
}

.header a {
    display: block;
    font-size: 0;
    transition: transform 0.3s ease;
    background: url(../assert/1.png) no-repeat;
    height: 200px;

}

.nav {
    display: flex;
    justify-content: space-between;
    margin: 0 auto;
    width: 1200px;
    height: 200px;
}

.nav ul li:nth-child(even) {
    width: 0.5px;
    height: 11px;
    background-color: #fff;
    margin: 4px 10px;
}

.nav ul li {
    float: left;
}